So the fascinating questions are: XY individuals with androgen insensitivity syndrome AIS due to a dysfunctional gene for the androgen receptor present as women and have feminine digit ratios on average, as would be predicted if androgenic hormones affect digit ratios. Digit ratio in men correlates with genetic variation in the androgen receptor gene. It should be noted, however, that the standard deviations associated with each given 2D: In other projects Wikimedia Commons.
Asian Journal of Andrology.
Digit ratio (2D:4D) in homosexual and heterosexual men from Austria.
Direct effects of sex hormones on bone growth might be responsible, either by regulation of Hox genes in digit development or independently of such genes. Lay summary — LiveScience 2 March Korean Journal of Physical Anthropology in Korean. The ratio of second to fourth digit lengths: Increased risk of breast cancer in females.
Men show a different pattern. That a greater proportion of men have shorter index fingers than ring fingers than do women was noted in the scientific literature several times through the late s,  with the statistically significant sex difference in a sample of men and women established by after which time the sex difference appears to have been largely forgotten or ignored. Wikimedia Commons has media related to Digit ratio. Thus some ethnic groups' confidence intervals overlap. This was not true for trans men, however, who were within the average range for biological females. Finger length may be an indication of sexual orientation, a controversial study has shown. Inactivation of AR decreases growth of digit 4, which causes a higher 2D: